"One fascinating thing is a lot of the people I have met through diving - kings and queens, film stars and experts," he said.
"I have been very happy that I get invited by very interesting people to go away and dive with them."
Mr Bennett has swum alongside whale sharks in West Papau and been snuck up on by a Queensland grouper - regarded as the biggest fish with weights of up to 400kg - in Three Kings, Australia.
"Once I was diving on a seamount off the Cocos Islands called Alcyone, and was surrounded by hundreds of hammerhead sharks.
"They are really weird things, but they are just amazing - they have eyes out on the ends of those things and they swim in a funny pattern.
"By mistake I jumped on a great white shark once, and also another amazing thing is swimming with whale sharks up to 35 or 40 feet long."
It's not only deep sea creatures that keep drawing Mr Bennett back to the ocean - his Napier Hill home is an anthology of human misadventure.
There is a Greek amphora so old it looks fossilised.
"It was in a hole and I had to take my gear off to get it out, then take the bits back and reassemble in London."
He has an artifact from the wreck of a ship sunk in the 1700s, charcoal black from the Baltic Sea.
"That happens when it's been down there for two or three hundred years."
Then there's the treasure.
"Kelly Tarlton is one of my best diving mates and we were diving the wreck of the SS Tasmania at Mahia trying to get the Rothschild jewels.
"My flash reflected off something in the sand and I found this beautiful pin with five diamonds in it."
His bookshelf is a library of deep sea exploration, and atop sits a Sarrah Star.
"They gave it to me once. It's like the Oscars of the diving world."
The retired optometrist, of Visique Bennett & Pearson Optometrists, cut his teeth in Hawke's Bay waters, learning to snorkel in a dam on his grandparents' Dannevirke farm.
"I was very small and I don't know, something just twigged," he said.
Aged 18, he headed to study the family trade at London's City University.
"I did fall on my feet rather and dived with the right people, then I was involved with photography for a couple of books and went on to write articles for dive magazines all around the world."
His summer job was running the biggest dive school in the United Kingdom, and when he completed his thesis in underwater vision was involved in a number of groundbreaking experiments.
"I worked with the United States Airforce School of Aerospace Medicine.
"They were having problems with astronauts not being able to see in space and had some theories about that.
"I was able to clear up one."
In Britain he worked with the Royal Aircraft Establishment in Farnborough before a two-year stint in Sweden, returning to the Bay in 1967 to join his father's practice.
"I practised with my father and he was a great diver as well, he was my best buddy and great to work with."
He married a Swedish woman and had two daughters - Annika and Camilla.
He has also worked with the Antarctic Research Programme, introduced the modern dry suit to New Zealand and developed prescription diving masks and other gear.
In Hawke's Bay he enjoys diving in a collection of "secret lakes", most of them on private farmland he would not reveal to protect their delicate eco-systems.
His biggest disappointment is the way local marine life has depleted.
"I know what it was like diving here in the 1950s and I know what it is like now."
